You may find this passionately-discussed thread regarding writing to the top of a file (#354830) useful here as well. Among the ideas presented are:
  1. Using linked lists to avoid moving stuff around once it's written to a file, and
  2. Using a filesystem that doesn't rely on clustering.

In reply to Re: Combining Ultra-Dynamic Files to Avoid Clustering (Ideas?) by Dr. Mu
in thread Combining Ultra-Dynamic Files to Avoid Clustering (Ideas?) by rjahrman

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